Two major Chinese courier companies announced price rises on Tuesday and Wednesday ahead of Nov. 11, which is expected to be China's largest ever online shopping festival.

Better services, according to ZTO Express and Yunda Express, mean rising costs in labor, materials and transportation, but neither company was prepared to say by how much prices would rise. Other domestic couriers are expected to follow suit.

Wang Chao, a deliveryman with ZTO Express, said he usually works 11 or 12 hours a day. "I hear that it is just a slight rise and won't make a big difference, but we will earn a little more," he said.

China Express Association predicts that the industry will handle more than 1 billion packages between Nov. 11 and Nov. 16.

Nov. 11 is "Singles Day," allegedly started by some college students in the 1990s to celebrate -- or poke fun at -- their unattached status. Nov. 11 was chosen for the four solitary digits: 11-11.

It has grown into a Chinese version of Cyber Monday, the Monday after Thanksgiving in theUnited States, and promoted as an online shopping day.

Alibaba began Singles Day campaigning in 2009. TMall, Alibaba's online marketplace, made only 50 million yuan (7.6 million U.S. dollars) back then. Last year, the figure reached 120 billion yuan.

On the back of the e-commerce boom, China's courier sector has been the world's largest in terms of delivery volume for three years but continual expansion has put heavy pressure on services, leading to problems in delivery delays and driver safety.

Lai Yang, a researcher in logistics, attributed the price rises to a shortage of labor.